ofxCvBlob

ofxCvBlob represents an area identified by the OpenCV plug-in as being a contiguous object in the scene. It's most often stored within a contrountFind instance and populated by a call to findContours().

In the image below you can see two blobs detected in the grayscale image:

float ofxCvBlob::area

ofRectangle ofxCvBlob::boundingRect

an ofRectangle instance that can be drawn to the screen and that shows the height and width of the blob. This can be helpful to determine large regions of interest, or it can lead to some inaccurate results depending on the shape of your object. For instance, a squarish shape will be well represented by a rectangle, whereas a long thin shape with an angle in the middle will not.

float ofxCvBlob::length

int ofxCvBlob::nPts

vector ofxCvBlob::pts

This is a vector of ofPoint objects that represent the contour of the blob. This is different from the bounding rectangle. It's listing the different points around the edge of the blob. The bounding rectangle is a rectangle around the extreme points of the blob.

If you have any doubt about the usage of this module you can ask in the forum.

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